Gun fu is the style of sophisticated close-quarters gunplay seen in Hong Kong action cinema and in Western films influenced by it. It often resembles a martial arts battle played out with firearms instead of traditional weapons.

The focus of gun fu is style, and the usage of firearms in ways that they were not designed to be used. Shooting a gun from each hand, shots from behind the back, as well as the use of guns as melee weapons are all common. Other moves can involve shotguns, Uzis, rocket launchers, and just about anything else that can be worked into a cinematic shot. It is often mixed with hand-to-hand combat maneuvers.

"Gun fu" has become a staple factor in modern action films due to its visually appealing nature (regardless of its actual practicality in a real-life combat situation). This is a contrast to American action movies of the 1980s which focused more on heavy weaponry and outright brute-force in firearm-based combat.

Before 1986, Hong Kong cinema was firmly rooted in two genres: the martial arts film and the comedy. Gunplay was not terribly popular because audiences had considered it boring, compared to fancy kung-fu moves or graceful swordplay of the wu shuepics. What moviegoers needed was a new way to present gunplay-- to show it as a skill that could be honed, integrating the acrobatics and grace of the traditional martial arts. And that's exactly what John Woo did. Using all of the visual techniques available to him (tracking shots, dolly-ins, slo-mo), Woo created beautifully surrealistic action sequences that were a 'guilty pleasure' to watch. There is also intimacy found in the gunplay-- typically, his protagonists and antagonists will have a profound understanding of one another and will meet face-to-face, in a tense Mexican standoff where they each point their weapons at one another and trade words.

The popularity of John Woo's films, and the heroic bloodshed genre in general, in the West helped give the gun fu style greater visibility. Film-makers like Robert Rodriguez were inspired to create action sequences modelled on the Hong Kong style. One of the first to demonstrate this was Rodriguez's Desperado (1995). The Matrix (1999) played a part in making "gun fu" the most popular form of firearm-based combat in cinema worldwide; since then, the style has become a staple of modern Western action films.